Sample sites for obtaining fluid access to a patient's circulatory system are well known. For example, a catheter inserted into a patient's blood vessel may be connected to a sample site such as shown in U.S. Pat. No. 4,874,377, the disclosure of which is fully incorporated herein by reference. Alternatively, the sample site may be in-line with tubing connecting the catheter to a blood pressure monitoring transducer and/or a supply of saline or other solution, such as shown in co-pending application Ser. No. 577,153 filed Sep. 4, 1990 mailed Aug. 30, 1990 and received in the U.S. Patent and Trademark Office Sep. 4, 1990, entitled "Method and Apparatus for Sampling Blood," in the name of Phillip D. Messinger (the "Messinger application"), and which is a continuation-in-part of Ser. No. 07/524,224 filed May 15, 1990, now U.S. Pat. No. 5,048,537, the disclosures of which are fully incorporated herein by reference.
Typical of sample sites is that they include a housing having a liquid path extending therein and which is to be coupled to the patient's circulatory system to make the fluid connection such as through a catheter and/or the tubing of an intravenous system, for example, like the blood pressure monitoring apparatus shown in the aforementioned patent applications. A sample site further typically includes an access port through which fluids may be introduced into the patient's circulatory system or from which blood may be withdrawn from the patient, both via the liquid path. By way of example, a needle may be received through a resilient stopper in the access port and on into the liquid path to couple a syringe or the like attached to the needle with the patient's circulatory system for injection/withdrawal of fluids. However, sampling sites requiring use of a needle present significant risks from needle sticks. As will be readily appreciated, needle sticks provide a mechanism for transfer of dangerous diseases, such as hepatitis or AIDS.
To reduce risk of needle sticks, sampling sites have been developed which eliminate needles. Such sampling sites provide an access port adapted for needleless connection with an external fluidic system such as a syringe or tubing. To this end, a cylindrical reservoir is provided on the sample site to provide a confined conduit between the needleless connector such as a male Luer connector and a valve assembly within the sample site. One example is the stopcock side port shown in FIG. 5 in the aforementioned Messinger application in which the external fluidic system is connected thereto by securing the cuff of a male Luer lock connector to the flanged top of a reservoir defined by the cylindrical wall of a female Luer connector. Other needleless access ports are provided in which a blunt cannula, such as the tip or taper of a male Luer connector, is receivable into the cylindrical reservoir. As shown, for example, in aforementioned U.S. Pat. No. 4,874,377, the male Luer connector tip impacts the valve assembly at the bottom of the female Luer connector reservoir causing the valve to deflect and open under pressure of the tip of the male Luer connector thereagainst. As the valve assembly opens, a channel for fluid communication between the liquid path within the sample site and the external fluidic system is created.
While such needleless sample sites reduce or eliminate needle stick problems, the cylindrical reservoir by which to secure the male Luer connector to the sample site has introduced its own significant problems. In particular, the reservoir is difficult to clean and has prompted concern about contamination and the dangers of bacterial growth therein.